Hinge design for enhanced optical performance for a digital micro-mirror device

ABSTRACT

An apparatus for use with a digital micro-mirror includes a hinge disposed outwardly from a substrate. The hinge is capable of at least partially supporting a micro-mirror disposed outwardly from the hinge. The micro-mirror is capable of being selectively transitioned between an on-state position and an off-state position. In one particular embodiment, the hinge comprises a substantially flat profile for at least a portion of the hinge disposed between a first hinge post of the hinge and a mid-point of the hinge. The apparatus also includes a plurality of process control voids formed within a conductive layer disposed inwardly from the hinge. In one particular embodiment, the substantially flat profile is at least partially created from the plurality of process control voids.

TECHNICAL FIELD OF THE INVENTION

This invention relates in general to optical processing devices and, inparticular, to an apparatus having an improved hinge design and methodof manufacturing the same.

BACKGROUND

Digital micro-mirror devices (DMD) are capable of being used in opticalcommunication and/or projection display systems. DMDs involve an arrayof micro-mirrors that selectively communicate at least a portion of anoptical signal or light beam. DMDs selectively communicate an opticalsignal or light beam by pivoting between active “on” and “off” states.To permit the micro-mirrors to pivot, each micro-mirror is attached to ahinge that is mounted on one or more support posts.

Conventional DMDs typically formed a sloped and/or sagged hinge profilein an attempt to minimize the effect of “popped” hinges that formedafter final annealing of the DMD. Although the sloped and/or saggedprofile attempted to minimize the effect of “popped” hinges, in somecases, the sloped and/or sagged profile is still susceptible todeveloping the “popped” hinges. In addition, the conventional hingeshaving the sloped and/or sagged profile typically exhibit poor dim lineartifact.

SUMMARY

In one embodiment, an apparatus for use with a digital micro-mirrorcomprises a hinge disposed outwardly from a substrate. The hinge iscapable of at least partially supporting a micro-mirror disposedoutwardly from the hinge. The micro-mirror is capable of beingselectively transitioned between an on-state position and an off-stateposition. In one particular embodiment, the hinge comprises asubstantially flat profile for at least a portion of the hinge disposedbetween a first hinge post of the hinge and a mid-point of the hinge.The apparatus also comprises a plurality of process control voids formedwithin a conductive layer disposed inwardly from the hinge. In oneparticular embodiment, the substantially flat profile is at leastpartially created from the plurality of process control voids.

In a method embodiment, a method of forming an apparatus for use with adigital micro-mirror comprises forming a plurality of process controlvoids within a conductive layer disposed outwardly from a substrate. Theplurality of process control voids define an intermediate profile of ahinge. The method also comprises forming a hinge layer disposedoutwardly from the conductive layer. The hinge layer having theintermediate profile. In one particular embodiment, the intermediateprofile comprises an approximately sinusoidal profile having a height ofa mid-point that is substantially similar to a height of a first hingepost of the apparatus.

Depending on the specific features implemented, particular embodimentsof the present invention may exhibit some, none, or all of the followingtechnical advantages. Various embodiments may be capable of minimizingthe likelihood of popped hinges after annealing the device. Someembodiments may be capable of providing an improved dim lineperformance.

Other technical advantages will be readily apparent to one skilled inthe art from the following figures, description and claims. Moreover,while specific advantages have been enumerated, various embodiments mayinclude all, some or none of the enumerated advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and forfurther features and advantages thereof, reference is now made to thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a perspective view of one embodiment of a portion of a digitalmicro-mirror device;

FIG. 2 is a top view of a partially formed digital micro-mirror pixel;

FIGS. 3A through 3E are cross sectional views illustrating one exampleof a method of forming a portion of a digital micro-mirror device; and

FIGS. 4A through 4C are a cross sectional view of a hinge profile beforesubjecting the hinge to an anneal process.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 is a perspective view of one embodiment of a portion of a digitalmicro-mirror device (DMD) 100. In this example, DMD 100 comprises amicro electro-mechanical switching (MEMS) device that includes an arrayof hundreds of thousands of tilting micro-mirrors 104. In this example,each micro-mirror 104 is approximately 13.7 square microns in size andhas an approximately one micron gap between adjacent micro-mirrors. Insome examples, each micro-mirror can be less than thirteen squaremicrons in size. In other examples, each micro-mirror can beapproximately seventeen square microns in size. In addition, eachmicro-mirror 104 may tilt up to plus or minus ten degrees creating anactive “on” state condition or an active “off” state condition. In otherexamples, each micro-mirror 104 may tilt plus or minus twelve degreesfor the active “on” state or “off” state.

In this example, each micro-mirror 104 transitions between its active“on” and “off” states to selectively communicate at least a portion ofan optical signal or light beam. To permit micro-mirrors 104 to tilt,each micro-mirror 104 is attached to one or more hinges 116 mounted onhinge posts 108, and spaced by means of an air gap over a complementarymetal-oxide semiconductor (CMOS) substrate 102. In this example,micro-mirrors 104 tilt in the positive or negative direction until yoke106 contacts conductive conduits 110. Although this example includesyoke 106, other examples may eliminate yoke 106. In those examples,micro-mirrors 104 tilt in the positive or negative direction untilmicro-mirrors 104 contact a mirror stop (not explicitly shown).

In this particular example, electrodes 112 and conductive conduits 110are formed within a conductive layer 120 disposed outwardly from anoxide layer 103. Conductive layer 120 can comprise, for example, analuminum alloy or other suitable conductive material. Oxide layer 103operates to insolate CMOS substrate 102 from electrodes 112 andconductive conduits 110.

Conductive layer 120 receives a bias voltage that at least partiallycontributes to the creation of the electrostatic forces developedbetween electrodes 112, micro-mirrors 104, and/or yoke 106. In thisparticular example, the bias voltage comprises a steady-state voltage.That is, the bias voltage applied to conductive layer 120 remainssubstantially constant while DMD 100 is in operation. In this example,the bias voltage comprises approximately twenty-six volts. Although thisexample uses a bias voltage of twenty-six volts, other bias voltages maybe used without departing from the scope of the present disclosure.

In this particular example, CMOS substrate 102 comprises the controlcircuitry associated with DMD 100. The control circuitry can compriseany hardware, software, firmware, or combination thereof capable of atleast partially contributing to the creation of the electrostatic forcesbetween electrodes 112, micro-mirrors 104, and/or yoke 106. The controlcircuitry associated with CMOS substrate 102 functions to selectivelytransition micro-mirrors 104 between “on” state and “off” state based atleast in part on data received from a processor (not explicitly shown).

In this particular example, micro-mirror 104 a is positioned in theactive “on” state condition, while micro-mirror 104 b is positioned inthe active “off” state condition. The control circuitry transitionsmicro-mirrors 104 between “on” and “off” states by selectively applyinga control voltage to at least one of the electrodes 112 associated witha particular micro-mirror 104. For example, to transition micro-mirror104 b to the active “on” state condition, the control circuitry removesthe control voltage from electrode 112 b and applies the control voltageto electrode 112 a. In this example, the control voltage comprisesapproximately three volts. Although this example uses a control voltageof approximately three volts, other control voltages may be used withoutdeparting from the scope of the present disclosure.

Conventional DMDs typically include a hinge that has a sloped profilebetween the hinge posts and a mid-point associated with the hinge. Thatis, at least a portion of the hinge disposed between the hinge post andthe mid-point has a height that is substantially different than a heightof the hinge post. In most cases, at least a portion of the hingedisposed between the hinge post and the mid-point has a height that isdifferent than a height of the hinge post by at least six-hundredAngstroms.

In addition, conventional DMDs typically form a hinge by depositing ahinge material in a sagged profile between the hinge posts associatedwith the hinge. That is, a hinge profile that has a mid-pointsubstantially below a plane defined by a height associated with eachhinge post. The terms “above” and/or “below” refer to the proximity of acomponent in relation to another component of the DMD and are notintended to limit the orientation of the device and/or components. Inmost cases, the sagged profile associated with the hinge of theconventional device is greater than two-hundred fifty Angstroms.

Conventional DMDs typically formed the sloped and/or sagged profile inan attempt to minimize the effect of “popped” hinges that formed afterfinal annealing of the DMD. A “popped” hinge refers to a hinge having atleast a portion of a hinge profile that is disposed substantially abovea plane defined by a height associated with each hinge post. Althoughthe sloped and/or sagged profile attempted to minimize the effect of“popped” hinges, in some cases, the sloped and/or sagged profile isstill susceptible to developing the “popped” hinges. In addition, theconventional hinges having the sloped and/or sagged profile typicallyexhibit poor dim line performance.

Unlike conventional DMDs, DMD 100 comprises a hinge 116 that has asubstantially flat hinge profile between a hinge post 108 and amid-point (not explicitly shown) of hinge 116. That is, the portion ofhinge 116 disposed between hinge post 108 and the mid-point has a heightthat is substantially similar to a height of hinge post 108. In mostcases, the portion of hinge 116 disposed between hinge post 108 and themid-point has a height that is within two-hundred fifty Angstroms of aheight of hinge post 108. In other cases, the portion of hinge 116disposed between hinge post 108 and the mid-point has a height that iswithin one-hundred fifty Angstroms of a height of hinge post 108.

To obtain the substantially flat hinge profile, hinge 116 ismanufactured by forming an approximately sinusoidal hinge profilebetween hinge posts 108 (as illustrated in FIGS. 3A-3D). The term“approximately sinusoidal profile” refers to a hinge profile that has amid-point at approximately the same height as a plane defined by eachhinge post and is not intended to limit the shape of the hinge profileto a sinusoid. In some cases, the mid-point can be within twentyAngstroms above or below the plane, and in other cases, the mid-pointcan be no more than thirty Angstroms below the plane; these are allinstances of an approximately sinusoidal hinge. In particularembodiments, the approximately sinusoidal hinge profile comprisesapproximately two or more periods or repetitions in shape.

One aspect of this disclosure recognizes that by forming hinge 116having a substantially flat hinge profile device manufactures canimprove the yield by reducing the number of “popped” hinges. Inaddition, providing hinge 116 with a substantially flat hinge profiletypically reduces the jitter and/or bouncing that occurs as a result ofmicro-mirrors 104 transitioning between “on” and “off” states. Reducingthe jitter and/or bouncing tends to result in a reduced dim lineartifact of DMD 100.

FIG. 2 is a cut-away view of a portion of a micro-mirror assembly 150associated with a DMD. In FIG. 2, elements that are substantiallysimilar in structure and function to elements in FIG. 1 have the samereference numerals. In this example, assembly 150 includes hinge posts108, conductive conduits 110, and electrodes 112.

Micro-mirror assembly also includes a plurality of process control voids122 formed within conductive layer 120. As used in this document, theterms “patterned trench” and “process control voids” are usedinter-changeably. Process control voids 122 operate to selectivelydisplace a spacer layer material formed between hinge posts 108.Selectively displacing the spacer layer material formed between hingeposts 108 can advantageously allow device manufacturers to control aprofile and/or shape of a spacer layer during its formation. Controllingthe profile and/or shape of the spacer layer allows a devicemanufacturer to control a shape and/or profile of a subsequently formedhinge associated with assembly 150. In some cases, controlling theprofile and/or shape of the spacer layer can allow a device manufacturerto form an approximately sinusoidal hinge profile. Forming the patternof process control voids 122 may be effected through any of a variety ofprocesses, such as, by removing a portion of conductive layer 120.

FIGS. 3A through 3E are cross sectional views illustrating one exampleof a method of forming a portion of a digital micro-mirror device (DMD)300. DMD 300 may be used as a basis for forming any of a variety ofoptical devices, such as a spatial light modulator, a gain equalizer, anoptical filter, or combination of these or other optical devices.Particular examples and dimensions specified throughout this documentare intended for example purposes only, and are not intended to limitthe scope of the present disclosure. Moreover, the illustration in FIGS.3A through 3E are not intended to be to scale.

FIG. 3A shows a cross sectional view of DMD 300 after formation of ainter-level oxide layer 304 disposed outwardly from a substrate 302 andafter formation of a conductive layer 306 outwardly from inter-leveloxide layer (ILO) 304. Although substrate 302 and inter-level oxidelayer 304 are shown as being formed without interstitial layers betweenthem, such interstitial layers could alternatively be formed withoutdeparting from the scope of the present disclosure. Substrate 302 maycomprise any suitable material used in semiconductor chip fabrication,such as silicon, poly-silicon, indium phosphide, germanium, or galliumarsenide. In various embodiments, substrate 302 can includecomplementary metal-oxide semiconductor (CMOS) circuitry capable ofcontrolling DMD 300 after its formation.

Inter-level oxide layer 304 may comprise, for example, oxide, silicondioxide, or oxi-nitride. Forming inter-level oxide layer 304 may beeffected through any of a variety of processes. In one non-limitingexample, inter-level oxide layer 304 can be formed by growing an oxide.Using a grown oxide as inter-level oxide layer 304 can advantageouslyprovide a mechanism for removing surface irregularities in substrate302. For example, as oxide is grown on the surface of substrate 302, aportion of substrate 302 is consumed, including at least some of thesurface irregularities.

Conductive layer 306 may comprise, for example, an aluminum alloy orother conductive material. Where conductive layer 306 comprises analuminum alloy, the aluminum alloy may comprise, for example, aluminum,silicon, polysilicon, tungsten, nitride, and/or a combination of theseor other conductive materials. In this example, conductive layer 306comprises silicon-based aluminum that has light absorbing and/oranti-reflective properties. In other embodiments, conductive layer 306may include an anti-reflective material disposed outwardly from thesilicon-based aluminum layer. Forming conductive layer 306 may beeffected, for example, by depositing silicon-based aluminum. Althoughinter-level oxide layer 304 and conductive layer 306 are shown as beingformed without interstitial layers between them, such interstitiallayers could alternatively be formed without departing from the scope ofthe present disclosure.

At some point, the conductive conduits, electrodes, and process controlvoids (not explicitly shown) associated with DMD 300 are formed withinconductive layer 306. Forming the conductive conduits, electrodes, andprocess control voids may be effected through any of a variety ofprocesses. For example, the conductive conduits, electrodes, and processcontrol voids may be formed by removing a portion of conductive layer306. In other embodiments, the process control voids can be formed byremoving a portion of inter-layer oxide layer 304 prior to the formationof conductive layer 306. In this particular embodiment, the conductiveconduits, electrodes, and process control voids are formed by patterningand etching conductive layer 306 using photo resist mask and etchtechniques. In some cases, the conductive conduits, electrodes, andprocess control voids can be formed substantially simultaneously. Inother embodiments, the conductive conduits, electrodes, and processcontrol voids can be formed subsequent to one another. In variousembodiments, the conductive conduits, electrodes, and process controlvoids formed in conductive layer 306 can be substantially similar instructure and function as conductive conduits 110, electrodes 112, andprocess control voids 122 of FIGS. 1 and 2A.

Forming the process control voids in conductive layer 306 can allow aDMD device manufacturer to control the profile and/or shape of a spacerlayer during its formation (to be formed later). Controlling the asformed shape of the spacer layer allows a device manufacturer to controlas formed shape of a subsequently formed hinge associated with DMD 300.

FIG. 3B shows a cross sectional view of DMD 300 after formation of aspacer layer 308 outwardly from inter-level oxide layer 304 and afterformation of hinge post cavities 309 a and 309 b within spacer layer308. Although spacer layer 308 and conductive layer 306 are shown asbeing formed without interstitial layers between them, such interstitiallayers could alternatively be formed without departing from the scope ofthe present disclosure. Spacer layer 308 may comprise, for example, aphotoresist material or other selectively etchable material. That is,spacer layer 308 can be removed using an etchant that does notsignificantly affect other materials.

Forming spacer layer 308 may be effected through any of a variety ofprocesses. For example, spacer layer 308 can be formed by depositing orspinning-on a photo-resist material. In the illustrated embodiment,spacer layer 308 comprises a material that is selectively etchable fromconductive layer 306 and/or inter-level oxide layer 304. That is, eachof spacer layer 308 and conductive layer 306 and/or inter-level oxidelayer 304 can be removed using an etchant that does not significantlyaffect the other.

In this particular example, spacer layer 308 is formed after formationof the process control voids within conductive layer 306. Forming theprocess control voids before forming spacer layer 308 allows devicemanufacturers to control a profile 307 of spacer layer 308. Profile 307depends at least in part on the location and pattern of the processcontrol voids. Controlling profile 307 can advantageously allow DMDdevice manufacturers to form a desired hinge profile. In some cases,profile 307 can allow device manufacturers to form an approximatelysinusoidal hinge profile.

Forming hinge post cavities 309 a and 309 b may be effected through anyof a variety of processes. For example, hinge post cavities 309 a and309 b can be formed by patterning and etching spacer layer 308.

FIG. 3C shows a cross sectional view of DMD 300 after formation of ahinge layer 310 outward from spacer layer 308. Although spacer layer 308and hinge layer 310 are shown as being formed without interstitiallayers between them, such interstitial could alternatively be formedwithout departing from the scope of the present disclosure. Forminghinge layer 310 may be effected through any of a variety of processes.For example, hinge layer 310 can be formed by depositing an aluminumalloy. Hinge layer 310 may comprise, for example, aluminum, silicon,polysilicon, tungsten, nitride, and/or a combination of these or othermaterials. In this example, hinge layer 310 comprises an aluminum alloythat has reflective properties. In other examples, hinge layer 310 couldcomprise an aluminum compound that has light absorbing and/oranti-reflective properties. Forming hinge layer 310 may be effected, forexample, by depositing an aluminum alloy.

In some cases, controlling the pattern associated with the processcontrol voids, the deposition rate, and/or other process parameters canallow a DMD device manufacturer to control hinge profile 311. In thisexample, the formation of hinge layer 310 results in at least a portionof hinge layer 310 having a hinge profile 311. Although hinge profile311 approximates a sinusoid in this example, any desired shape may beformed without departing from the scope of the present disclosure.

FIG. 3D shows a cross sectional view of DMD 300 after removal of spacerlayer 308. Spacer layer 308 can be removed by any of a number ofprocesses, such as, for example, by performing an isotropic plasma etch.Although this example illustrates the removal of spacer layer 308 afterdepositing hinge layer 310 without any additional process steps, suchadditional process steps could alternatively be performed withoutdeparting from the scope of the present disclosure.

In this particular embodiment, hinge profile 311 comprises anapproximately sinusoidal hinge profile having approximately two periodsor repetitions in shape. That is, hinge profile 311 has a mid-pointheight (X_(M)) at approximately the same height as a hinge post height(X_(H)) associated with hinge posts 312. In some cases, the mid-pointheight (X_(M)) can be within twenty Angstroms above or below the hingepost height (X_(H)). In other cases, the mid-point height (X_(M)) can beno more than thirty Angstroms below the hinge post height (X_(H)).

FIG. 3E shows a cross sectional view of DMD 300 after forming asubstantially flat hinge 314. Although this example illustrates formingsubstantially flat hinge 314 after removal of spacer layer 308 withoutany additional process steps, such additional process steps couldalternatively be performed without departing from the scope of thepresent disclosure.

Substantially flat hinge 314 can be formed by any of a number ofprocesses, such as, for example, by subjecting hinge layer 310 to ananneal process. In various embodiments, the anneal process can beperformed at a specified temperature for a desired period. The annealtemperature being based at least in part on an anneal time necessary toactivate the device. In various embodiments, the anneal process cancomprise subjecting hinge layer 310 to a temperature of betweenone-hundred degrees Celsius and two-hundred degree Celsius for nine tofifteen hours.

One aspect of this disclosure recognizes that forming an approximatelysinusoidal hinge profile 311 can allow DMD device manufacturers to forma hinge having a substantially flat profile. In this particularembodiment, hinge 314 comprises a substantially flat profile after theanneal process. That is, the portion of hinge 314 disposed between hingepost 312 and a mid-point 314 c has a height that is substantiallysimilar to a height associated with hinge post 312. In this particularembodiment, the portion of hinge 314 disposed between first end 314 aand mid-point 314 c has a height (X_(c)) that is within two-hundredfifty Angstroms of a height (X_(a)) associated first end 314 a. In someembodiments, the portion of hinge 314 disposed between second end 314 band mid-point 314 c has a height (X_(c)) that is within two-hundredfifty Angstroms of a height (X_(c)) associated with second end 314 b. Inother embodiments, the portion of hinge 314 disposed between first end314 a and mid-point 314 c has a height (X_(c)) that is withinone-hundred fifty Angstroms of a height (X_(a)) associated first end 314a.

One aspect of this disclosure recognizes that by forming hinge 314having a substantially flat hinge profile device manufactures canimprove the yield by reducing the number of “popped” micro-mirrors. Inaddition, providing hinge 314 with a substantially flat hinge profiletypically reduces the jitter and/or bouncing that occurs as a result ofthe micro-mirrors transitioning between “on” and “off” states. Reducingthe jitter and/or bouncing tends to result in an improved dim lineperformance of DMD 300.

FIG. 4A is a cross sectional view of a hinge profile 452 beforesubjecting a hinge to an anneal process. In this example, hinge profile452 comprises an approximately sinusoidal hinge profile between hingeposts 108 of FIG. 2. That is, hinge profile 452 has a mid-point height454 at approximately the same height as a plane 456 defined by a heightassociated with each hinge post 108. In this particular embodiment,mid-point height 454 is approximately two nanometers (e.g., twentyAngstroms) above plane 456. In other cases, mid-point height 454 can beno more than three nanometers (e.g., thirty Angstroms) below plane 456.

In this particular example, hinge profile 452 approximates a sinusoidhaving approximately two periods or repetitions in shape. Hinge profile452 includes valleys 458 a and 458 b defining a depth associated withhinge profile 452. Valleys 458 can comprise, for example, a depth of nomore than fourteen nanometers.

FIG. 4B is a cross sectional view of a hinge profile 462 beforesubjecting a hinge to an anneal process. In this example, hinge profile462 comprises an approximately sinusoidal hinge profile between hingeposts 108 of FIG. 2. That is, hinge profile 462 has a mid-point height464 at approximately the same height as a plane 466 defined by a heightassociated with each hinge post 108. In this particular embodiment,mid-point height 464 is approximately one nanometer (e.g., tenAngstroms) above plane 466. In other cases, mid-point height 464 can beno more than three nanometers (e.g., thirty Angstroms) below plane 466.

In this particular example, hinge profile 462 comprises approximatelytwo periods or repetitions in shape. Hinge profile 462 includes valleys468 a and 468 b defining a depth associated with hinge profile 462.Valleys 468 can comprise, for example, a depth of no more than tennanometers.

FIG. 4C is a cross sectional view of a hinge profile 472 beforesubjecting a hinge to an anneal process. In this example, hinge profile472 comprises an approximately sinusoidal hinge profile between hingeposts 108 of FIG. 2. That is, hinge profile 472 has a mid-point height474 at approximately the same height as a plane 476 defined by a heightassociated with each hinge post 108. In this particular embodiment,mid-point height 474 is approximately 1.5 nanometers (e.g., fifteenAngstroms) above plane 476. In other cases, mid-point height 474 can beno more than three nanometers (e.g., thirty Angstroms) below plane 476.

In this particular example, hinge profile 472 comprises approximatelytwo periods or repetitions in shape. Hinge profile 472 includes valleys478 a and 478 b defining a depth associated with hinge profile 472.Valleys 478 can comprise, for example, a depth of no more than sixteennanometers.

Although the present invention has been described in severalembodiments, a myriad of changes, variations, alterations,transformations, and modifications may be suggested to one skilled inthe art, and it is intended that the present invention encompass suchchanges, variations, alterations, transformations, and modifications asfalling within the spirit and scope of the appended claims.

1-20. (canceled)
 21. A method of forming a micromechanical devicecomprising: forming a hinge structure having a substantially sinusoidalprofile; and forming a deflectable member supported by said hingestructure.
 22. The method of claim 21, said forming a hinge structurecomprising forming a hinge structure having a substantially sinusoidalprofile of approximately two periods.
 23. The method of claim 21,comprising: forming a plurality of process control voids to influencesaid profile of said hinge structure.
 24. The method of claim 21, saidforming a hinge structure comprising forming a hinge structure having amid-point and two end-points spaced apart from a substrate at a heightrelative to a plane of a substrate within 150 Angstroms of each other.25. The method of claim 21, said forming a hinge structure comprisingforming a hinge structure of an aluminum alloy.
 26. The method of claim21, comprising: annealing said hinge structure.
 27. The method of claim21, said forming a deflectable member comprising forming a deflectablemirror.
 28. An apparatus comprising: a hinge structure having asubstantially sinusoidal profile; and a deflectable member supported bysaid hinge structure.
 29. The apparatus of claim 28, said hingestructure having a substantially sinusoidal profile of approximately twoperiods.
 30. The apparatus of claim 28, said hinge structure having amid-point and two end-points spaced apart from a substrate at heightsrelative to a plane of a substrate within 150 Angstroms of each other.31. The apparatus of claim 28, said hinge structure formed of analuminum alloy.
 32. The apparatus of claim 28, said hinge structurecomprising an annealed metal.
 33. The apparatus of claim 28, saiddeflectable member comprising a deflectable mirror.
 34. A method offorming a micromechanical device comprising: providing a substrate;forming a hinge support structure on said substrate; depositing a spacerlayer supported by said substrate; forming a hinge structure supportedby said hinge support structure and having a substantially sinusoidalprofile; forming a deflectable member supported by said hinge structure;and removing said spacer layer.
 35. The method of claim 34, said forminga hinge structure comprising forming a hinge structure having asubstantially sinusoidal profile of approximately two periods.
 36. Themethod of claim 34, comprising: forming a plurality of process controlvoids to influence said profile of said hinge structure.
 37. The methodof claim 34, said forming a hinge structure comprising forming a hingestructure having a mid-point and two end-points spaced apart from saidsubstrate at heights relative to said substrate within 150 Angstroms ofeach other.
 38. The method of claim 34, said forming a hinge structurecomprising forming a hinge structure of an aluminum alloy.
 39. Themethod of claim 34, comprising: annealing said hinge structure.
 40. Themethod of claim 34, said forming a deflectable member comprising forminga deflectable mirror.